For thousands of years, since before the age of the Roman Empire, man has used various implements for the separation of solid substances from fluids in which they may be suspended, or to separate solids of one size from solids having a different size. Such separation implements which separate mixtures of materials having differences in physical size or being in different physical states, i.e., solid versus liquid phase, are known by various terms including, but not necessarily limited to, sieves, strainers, colanders and the like. For purposes of ease of discussion, the general class of separating devices will be referred to herein as straining devices.
Generally speaking, the structure of most straining devices comprises a container or bowl portion into which the mixture or slurry of materials to be strained or separated is poured and at least briefly contained. Usually, the bottom, and sometimes the sides, of the container portion has a plurality of openings. The openings are sized to permit either the passage of that material which one desires to collect or to retain that material which one seeks to keep.
Optional components of a strainer which would be used in food preparation are a handle by which the user holds the strainer and legs on which the strainer may be rested while the materials to be strained are poured from a primary holding container into the strainer itself. Known handles include a straight member extending horizontally from an upper edge or rim of the strainer or its container portion. Another known version of a strainer is shaped much like a coffee mug having on or more handles, each of which is D-shaped and projects horizontally in an outward direction (rather than vertically and in a downward direction) from the upper edge or rim of the strainer or its container portion.
The addition of one or more handles or legs to the basic structure developed out of the need to be able to strain hot mixtures. The handles allow a user to hold the strainer with his hands at a safe distance from the container portion while pouring in the hot mixture. However, a strainer having a single handle suffers from the disadvantage that a single, lone user has only one hand available for lifting the container holding the hot mixture since the other hand must control the strainer itself. Additionally, the wrist of the hand holding the strainer is subjected to a great strain due to the torque when the mixture is initially placed in the strainer.
The addition of legs to a strainer allows the user to place the strainer on an even surface, thus freeing both hands for lifting the container having the hot mixture. However, this structure suffers from the disadvantage that it requires the user to place the strainer onto a surface which will drain away the liquid (where straining edibles and comestibles). Most commonly, the only suitable surface for draining away water from a strainer placed thereon in most households is the kitchen sink. However, when a cook is preparing a meal, the kitchen sink can become the most valuable of all the real estate in a kitchen and it can actually be a hardship to devote all or nearly all of the sink to a strainer. Additionally, it may occur that the bottom of the kitchen sink is already occuppied by other items such as dirty dishes, vegetable peels, etc. These must be removed prior to resting a strainer on the sink bottom, thereby requiring additional time and energy when these are in short supply and it may be most inconvenient. Failure to remove such objects leads to the possibility that the strainer will tip over, spilling its contents. Moreover, the contents of the strainer will come into contact with unhygienic or unsavory materials, such as food scrapings, dirty soap water, and the like and may become contaminated thereby.
It should particularly be noted that the basic design of the strainer has not substantially changed from a structural standpoint in thousands of years and that the known strainers and colanders of today's manufacture still suffer from the above disadvantages as did their ancestors many centuries ago. Although advanced modern materials have been developed for manufacturing the modern strainer and colander, i.e., most notably the plastics polyethylene, polypropylene and copolymers, the structure has remained relatively unchanged.